The objective of the proposed research is to investigate the role of cyclic AMP (cAMP) in remodeling bone surrounding erupting, resorbing and moving teeth. A method for the measurement of cAMP in bone has been developed in our laboratory. The tissue sample is extracted with water in a manner which eliminates substances that interfere with the subsequent protein binding assay for cAMP. Using this technique values of cAMP were obtained in chick and cat bones, and were found to be 0.4 plus or minus 0.03 pmoles/mg and 0.2-0.3 plus or minus 0.02 pmoles/mg respectively. Mechanically stressed bone surrounding tipped canines in cats demonstrated initial decrease in cAMP levels, followed by a 2-fold increase after 2-3 days. Bone samples will be removed from areas occlusal to erupting primary teeth in kittens following the completion of a serial radiographic study to determine optimal sampling time. Other samples will be obtained from around resorbing primary teeth in cats. Levels of cAMP will be assessed in these samples, and compared to those of neighboring areas in the jaw bones. Adenyl cyclase and phosphodiesterase activity will be measured in some of the bone samples, to determine their respective roles in altering intracellular concentrations of cAMP.